Glassing the Hull – inside

This is out of sequence from the construction manual, the next step is really fitting the deck. But I wanted to put the pages for glassing of the hull together. The main reason for that is to point out that the inside is much more difficult to do, both in just fairing the glass to the plywood in the open area, and especially in smoothly fitting the glass to the narrow areas at the bow and stern. The problems at the bow and stern can be anticipated, but what is not obvious is that the very straightforward fairing of the glass on the outside doesn’t translate at all to the inside. Even the slightest tension on the glass will tend to pull it up and away from the keel. As you smooth it, you constantly have to push the glass down toward the center and you have to pay attention to the whole length, over and over. Enough said.

glass is draped in the hull for trimming

Ready to Cut

Applying the glass on the inside (right) requires a tape line essentially along a waterline, all the way around. The glass will be trimmed later to this line, plus it establishes where you tape in the glass and cut the two triangles. Here the full rectangular sheet of glass is draped into the hull and taped on one side. It’s faired down into the bottom and ready to be cut, which will provide a long triangle of glass to do the other end of the hull.

the glass covers the interior of the hull

Ready to Epoxy

The remaining triangle of glass is in place (left). Note that there is sufficient length to provide an overlap in the middle of the hull. Be careful when trimming. Even when you leave more than an inch of margin, sometimes the cloth will fool you. When you start wetting it out and the cloth is definitely hugging the surface, the weave may “walk” the cloth unexpectedly. You can control this, to a large extent, but you have to be careful of wrinkles if the cloth isn’t lying without distortion of the weave.

you can see the masking tape under the curing glass

Ready to Trim

Here (right), the resin has been applied and cured for about 10 hours and is ready for trimming. Even though it might appear that it has already been trimmed, the wet cloth is just lying flat to the tape. Smooth, moderate razor blade pressure cuts the glass and the whole ragged edge comes away with the tape. But this leaves a very sharp ridge at the edge of the glass. Note that the glass looks smooth in the bow. This is a bit deceiving–I guarantee that as you wet the cloth towards the bow and stern, you will wind up using your scissors on the wet cloth, to relieve the fold and to create two flaps to overlap into the wedge. I found myself pressed for time as I fiddled with getting it right, as the resin was beginning to set up. It got easier with each bow/stern I did and by the time I got to the Coho I was willing to accept less than a perfectly faired outcome. Just don’t leave any gaps under the resin and your hull will be fine.

scraping the trimmed edge

Scraping the Edge of the Glass

I made it a point to scrape all edges, those of the trimmed glass and also both sides of the tape. Remember, at this point the deck has already been glassed on the inside. There are multiple runs of tape and patches of glass on the underside of the deck that will definitely scratch your knees and toes (not to mention your waterproof bags), if they aren’t smoothed/scraped. You can see here that the scraped edges of the glass tend to look as if the masking tape is still in place. It is not. That’s just the milky look of the 1/2″ or so of taped edge as a result of using the scraper. As you can see, the glass and resin come off together like curls of carved wood, except that it’s white.